1. Field of the Invention
This invention relates to a DC electromagnet, particularly for a low voltage power switch such as a contactor, comprising a magnetic circuit equipped with a magnetic core fixed to at least one end of a vane-shaped armature with a flat polar face and equipped with a yoke having one flange with a flat polar face associated with the vane with an axial air gap.
It also relates to a simple process for manufacturing such an electromagnet.
2. Related Art
DC electromagnets, particularly as used in contactors, are made in various shapes. The magnetic circuit for this type of electromagnet is frequently used with at least one permanent magnet that polarizes the magnetic circuit. Document FR-2 586 324 describes such a magnetic circuit, the vanes being shrink fitted on the core and fixed in contact with shoulders machined on the core.
When the electromagnet comprises two pairs of polar faces, one of which is formed by the vane and the yoke and the other is formed by another vane or polar spreading of the core and by the yoke, the relative position of the,polar faces needs to be adjusted.
Another purpose of the invention is to simplify manufacture of a DC electromagnet and to adjust pairs of polar faces of such an electromagnet.
According to the invention, the core is smooth and the vane is shrink fitted and fixed on the end of the smooth core in an adjustable position determined by application on the plane polar face of the flange of the associated yoke.
Preferably, the magnetic circuit has two parallel vanes fixed to the two ends of the core, namely a first vane put in a reference position, and a second vane. The second vane is adjusted by firstly placing the first vane, that has been fixed to the core, on the polar face of the associated first flange, and then sliding the second vane on the smooth core until it reaches a stop position on the polar face of the associated second flange, and the second vane is attached to the core while in this stop position.
The two vanes can cooperate with the flanges of the magnetic circuit, the polar faces of which are oriented in the same direction, the first vane being applied in contact with the first flange on the inner side of the magnetic circuit and the second vane applied on the second flange on the outer side of the magnetic circuit.